Alarm system with automatic ringback

ABSTRACT

An alarm system which senses, at a central location, change from day monitoring to night monitoring at the remote location and automatically sends a ringback signal to the remote location to indicate that the change has been received and noted. The ringback signal is a repetitive signal for a given number of repetitions. The central location includes an indication of the change which remains activated until the central monitor is reset and switched to night monitoring.

United States Patent [191 Damon Dec. 10, 1974' 3,618,082 11/1971 Feulner340/413 Primary ExaminerJohn W. Caldwell [76] Inventor: Clarence StanleyDamon, 6758 Penn I Kansas City 641 I3 Assistant Examiner-Richard P.Lange Attorney, Agent, or FirmFidelman, Wolffe, Leitner 22 Filed: Sept.18, 1973 & Hiney [21] Appl. No.: 398,301

- ABSTRACT 340/226 A'n alarm system which senses, at a central location,hilt. Cl. hange from day monitoring to night monitoring at the Fleld ofSearch 340/2131, remote location and automatically sends a ringback 3l4, 163, 413 signal to the remote location to indicate that the changehas been received and noted. The ringback References Cited signal is arepetitive signal for a given number of repe- UNITED STATES PATENTStitions. The central location includes an indication of 2,978,676 4/1961Spencer 340/226 the Change which remains activated until the Central 3 09 73 12 9 2 w et aL I I I I 340/226 monitor is reset and switched tonight monitoring.

3,287,7l7 ll/l966 Kraus r 340/2l3.l I 3,585.620 6/1971 Durand 340/213218 Clams 2 Drawmg F'gures CENTRAL l0 l r I. 1 I I l I TAZ ZONE 1 l l l iO 0% A I I? l "m4 I i I l l l I TBI l I T52 ZONE 1 T83 B l T84 I l l l II I l l I I TCI [l3 r -"1I I6 I T4 0 ZONE 1C5 l ea f REMOTE c I -l 0 ocl I I OM I l l PATENTEL 1 01974 SHEEI 2 OF 2 1 ALARM SYSTEM WITHAUTOMATIC RINGBACK BACKGROUND OF THE INVENTION 1. Field of the InventionThe present invention relates generally to a centrally monitored remotealarm system and more particularly to an automatic ringback system forcentrally monitored remote alarm'systems.

2. Descriptionof Prior Art .In the field of centrally monitored alarmsystems, a plurality of remote locations are monitored at a centrallocation. At the remote location, there usually are a plurality ofswitches connected to various devices to be protected including a firstgroup for day-time monitoring and a second group .(including part of thefirst group) for night-time monitoring. A selection switch is includedat the remote location to connect the central office with either thegroup of day-time or the group of night-time switches at the remotelocation.

In the evening, a large number of stores in a given area close atapproximately the same time; i.e., 6:00 or 9:00 in the evening. At thistime, the remote systems are switched from day-time monitoring tonight-timing monitoring and the central office must indicate by aringback signal that the central office has received the change from dayto night monitoring and that the system appears in order andconsequently the client may leave the premises.

In the prior art devices, the operator at the central location must ringback each received signal manually. Consequently, the client mustsometimes wait 2-3 minutes or sometimes as long as 10 minutes for thebusy operator to ring back the received signal. To alleviate thisinconvenience to the client, some companies have provided additionalpersonnel at these peak hours. The

additional personnel required is unnecessary expense which is passed onto the client.

SUMMARY OF THE INVENTION The present invention overcomes theshortcomings of the prior art previously discussed by providing anautomatic ringback system wherein the central office senses the changingfrom day to night monitoring at the remote location and automaticallytransmits a ringback signal to indicate that the change has beenreceived and noted and that the alarm system is in operating order. Aringback signal is transmitted repeatedly for a given number of times.Upon the termination of the ringback signal, the client may leave thepremises knowing that the central location has received the day to nightchange. At the central location, an indicator is activated for eachclient to which a ringback signal has been transmitted and isextinguished only by resetting of the central monitoring unit andswitching the central monitoring unit from day to night monitoring. Thecentral unit contains a single DC power source. for use with a pluralityof monitoring circuits and a single AC generator for transmitting theringback signal to the plurality of remote units.

OBJECTS OF THE INVENTION An object of the present invention is toprovide an I automatic ringback system.

Another object is to provide a simple and inexpensive ringback systemfor alarms.

A further object of the invention is the provision of a single powersource and a single ringback signal generator for use with a pluralityof zone monitoring remote site alarm systems.

Another object is to provide an automatic ringback which is easilyincorporated into a present alarm system without major modification.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawmgs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of theoverall system including schematics of the central power system and theremote site switches;

FIG. 2 is a detailed schematic of the individual zone monitoring unitswith automatic ringback capability.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows, in block diagramform, a central office having a central power. supply unit 10 andindividual zone monitoring units 11, 12 and 13 and remote locations 14,15 and 16 connected respectively to zone monitoring units. The centralpower supply 10 has a DC source 17 having one side connected to ground18 which is connected to output terminal T1. Connected to the other sideof DC source 17 is lamp 19 which is also connected to terminal 20 ofrelay 21. Relay 21 includes a solenoid 22 having one side thereofconnected to the terminal 22 and the other side connected to ground 23.Also connected to ground'23 are the two ganged switch elements 24 and 25of relay 21. Switch element 25 connects terminal 20 to ground 23 andswitch element 24 connects terminal 26 to ground 23. Connected toterminal 26 is a bell 27 which is connected to a 20-cycle motorgenerator set 28 which is also connected to ground 29. The ungroundedside of motor and generator set 28 is connected to terminal T3. Thenegative side of the DC power source 17 is connected to terminal T4.

Upon activation of relay 21, solenoid 22 closes the switch elements 24and 25 to contacts 26 and 20, respectively, connecting light 19 with theDC source 17 and bell 27 with the AC signal from motor generator set 28.

Connected to the terminals T1-T4 of central power supply are terminalsTAl-TA4, terminals TBl-TB4, and TCl-TC4, respectively of zone monitoringunits 11, 12 and 13, respectively. Though showing only three units, thenumber of units may be increased and is limited only by the capacity ofthe central power supply system. The lamp 19, bell 27 and the 20-cyclemotor generator 28 are examples of devices which may be used.Consequently any equivalent indicating and AC signal generating devicemay be used.

Connected to terminals TAS, TBS and TC6 are remote site units l4, l5 and16, respectively. A simplified schematic of the remote site unit isshown at remote site 14. Generally, the remote site has a day-nightswitch 30 having a day terminal 31 with day switches 31A, 31B and dayresistor 31R connected in series to ground. A second terminal 32 is anight terminal having night switches 32A, 32B and night resistor 32Rconnected in series to ground. Also in the remote unit is a ringbackindicator 33 connected between the input line and ground. Devices 31A,31B, 32A and 32B may be either normally open or normally closed switcheswhich may be foil on windows, switches on doors, windows, safes and anydevice which is to be monitored during the day or night position ofswitch 30. If they are normally open switches, they are usually inparallel with the resistor so that the system can be monitored, whereasif they are normally closed switches, no resistors are needed. Theindividual resistors 31 and 32 are of different values such that thecontrol monitoring system 11 can sense which mode switch 30 is in.

As will be discussed more fully in the explanation of FIG. 2, uponmoving switch 30 from the day position 31 to the night position 32,central zone monitoring unit 11 will sense the change and automaticallytransmit back a signal from AC ringback signal generator 28 to activateringback indicator 33 in the remote location. Also, upon sensing thechanging of the position of switch 31, relay 21 is activated which inturn activates lamp 19 and bell 27 until reset by a central operator.

A detailed schematic of the zone monitoring unit 11 is shown in Hg. 2and has terminals TAl-TA4 connected respectively to terminals T1-T4 ofthe central power supply and terminal TA-5 connected to the remote siteunit 14. TAl and TA2 are connected to three position toggle switch 40 atswitcharms 41 and 42, respectively. Switcharms 41, 42 and 43 are gangedby a restoring spring 44, and are shown in their neutral positionresting on contacts 46, 48 and 49, respectively. In the reset position,the switcharms are moved up, arm

41 coming in contact with contact 45, 42 coming in contact with 47 and43 breaking contact with contact 49. For the test position, the switchis moved down and switcharm 41 breaks contact with contact 46, 42 breakscontact with contact 48, and 43 comes into contact with contact 50,which iis connected to terminal TA-3. Terminal TA-l is also connectedthrough resistors 51 and Zener diode 52 to terminal TA-4 and providescurrent regulation for the zone monitoring network.

Connected in parallel between contact 46 and terminal TA4 are two seriescircuits having lights 53 and 54, resistors 55 and 56, and siliconcontrol diodes (SCR) 57 and 58, respectively. Connected in parallel withlights 53 and S4 and series resistors 55 and 56 are resistors 59 and 60,respectively. Upon detection of a break 63 and 64 are connected to theoutput of transistors 71 which has capacitor 72 at its base and biasingresistors 73, 74 and 75. Transistor 71 amplifies a signal obtained I iby a variable voltage divider formed by resistor 76 and a movable tap.

The voltage across voltage dividing resistor 76 is determined by theresistance between 76 and the remote site. The resistance between theremote location and the central office may change due to opening of oneof the switches in the remote site, breaking of a line between theremote site and central location and a short between the remote site andcentral location. The resistance between 76 and remote site may bechanged also by varying the position of switch 77 having contact arms78, 79, 80 and 81 and positions A, B, C and D. When the four gangedcontact arms 78, 79, 80 and 81 of switch 77 are in the A position, thealarm system is in the night monitoring position. When the contact armsare in the B position, the alarm system is in the day monitoringposition. When the contact arms are in the C position, the alarm systemwill simulate an opening condition to test the zone monitoringelectronics, including SCR 57 and indicator light 53. When the contactarms are in the D position, the alarm system will simulate a groundingcondition to test the electronics, including SCR 58 and indicator light54.

The resistance from the remote location is connected to contact arm 78.In the day-time position, 78 is connected directly to resistor 82 whichis connected to parallel combination of voltage dividing resistors 76and capacitor 83. In the B, C and D positions of contact arms 78,resistor 84 is connected in series with resistor 82. Contact arm 79 isopen in the A and B position and in the C position, connects variableresistor 85 in parallel with a series combination of resistors 82, 84and capacitor 83. Resistance 85 is chosen to be large enough so as tosimulate a break or open circuit condition. In the D position, contactarm 79 connects resistor 86 between resistors 75 and 82 and is chosen soas to simulate a grounded condition. Connected in series between contact49 and terminal TA4 of switch 44 are variable resistor 87, meter 88,resistor 89 and parallel capacitor 90. Connected between meter 88 andresistor 89 is contact arm 78 of switch 77. In the neutral position ofswitch 40, contact arm 43 connects the resistance of the remote site viaterminal TA5 with meter 88 via contact 49. The condition of the remotesite is not only monitored by meter 88 but by the electronics includingSCRs 57 and 58 and indicators 53 and 54.

Connected to contact 46 of switch is relay coil 90 having contact arms91 and 92. In parallel with relay coil is capacitor 93 which, as will bedescribed later, provides a slow release of the relay. The parallelcombination of capacitor 93 and relay coil 90 is connected to variableresistor 94 which is connected to switch contact 95. When relay coil 90is activated, it will break its circuit with the power supply by movingcontact 92 out of engagement with contact 95 and into engagement withopen contact 96, but will retain contact arms 91 and 92 in their downposition for a time to be determined by the values of the capacitor 93and the relay coil 90. Contact 97 for contact arm 91 is connected topositions B, C and D of contact arm 81 of switch 77 and contact 98 isconnected to switch arm 43 of switch 40. Contact arm 81 of switch 77 isconnected to contact 50 of switch 40 and terminal TA3 and has its Aposition open and its B, C and D positions connected to contact 97. Itshould be noted that contact arm 80 of switch 77 has all four of itspositions open and is not connected in the circuit.

Connecting contact arm 92 to the anode of SCR 57 is the parallelcombination of capacitor 99 and resistor 100 and series resistor 101.Though capacitor 99 and resistors 100, 101 are shown between SCR 57 andcontact arm 92, 92 and 57 may be directly connected and the capacitor 99and resistors 100 and 101 may be connected in series with the parallelcombination of relay coil 90 and capacitor 93. As will be described morefully hereafter capacitor 99 and resistors 100, 101 provide a cyclelimiting function to limit the number of cycles relay coil 90 opens andcloses gang contact arms 91 and 92.

The anodes of SCRs'57 and 58 are connected to terminal TA2 throughswitch arm 42 and contact 48 by diodes 102 and 103, respectively. Diode103 prevents the ignition of light 54 upon the activation of SCR 57 anddiode 102 prevents the ignition of light 53 upon the activation of SCR58.

Since the alarm circuitry alone is not part of the present invention,only the operation of the automatic ringback system will be described indetail. Initially, the system is in the day monitoring condition whereinsaid switch 77has contact arms 78, 79, 80 and 81 in their B position.Switch 40 which has switch arms 41, 42 and 43 in'their neutral positioncontacting contact 46, 48 and 49, respectively. Relay coil 90 isdeactivated with contact arm 91 contacting contact 98 and contact arm 92contacting contact 95. With the switches in the position just described,the remote site is being monitored via terminal TA5, contact arm 91,contact 98, switch arm 43, contact 49, meter 88, contact arm 78 to themonitoring electronics. When the client at the remote site desires toleave his premises and switches his daynight switch to the night-timeposition, the monitoring electronics sense a' break in the system andactivates SCR 57. Upon activation of SCR 57, a series circuit is createdfrom the DC source 17 through terminals T4 and TA4, SCR 57, diode 102,contact 48, switch arm 42, terminalTAZ, terminal T2 to relay coil 22 toactivate indicator light 19 and bell 27. Also connected to the DC powersource 17 through SCR 57 is break indicator 53 via contact 46, switcharm 41, terminal TAl, and terminal T1, and relay coil 90 via resistors101, 100, capacitor 99, contact arm 92, contact 95, resistor 94, contact46, switch arm 41, terminal TA] and terminal TA2. Thus, on switching theremote site switch from the day to night position, SCR 57 is activatedand activates relay coil 22 and its indicators 19 and 27; indicatinglight 53, and relay coil 90.

Upon the activation of relay coil 90, contact arms 91 and 92 are movedto their down position. With contact arm 91 in contact with contact 97,and AC signal from motor generator set 28 is transmitted to the remotelocation to ring remote indicator buzzer 33 through terminals T3 andTA3, the switch contact arm 81, position B, contact 97, contact arm 91,and terminal TA5. When contact arm 92 moves out of engagement withcontact 95, the DC power supply is removed from relay coil 90 and itstarts to discharge through capacitor 93. Capacitor 93 prevents relaycoil 90 from immediately discharging and consequently holds contact arms91 and 92 in the down position for a preset amount of time, thusproducing more than momentary buzzing of remote indicator 33. Also, uponthe breaking of contact between contact arm 92 and contact 9, thecharging circuit for capacitor 99 was broken and a small amount ofcharge is bled off during this break by resistor 100. With the energy inrelay coil 90 being diss'ipated, contact arms 91 and 92'resume theirupward position, cutting off the AC signal through terminal TAS andreactivating the charging circuit of the capacitor 99 and relay coil 90.The cycle is then repeated as 1 just described.

The number of times the cycle will be repeated so as to allow thecontact arms 91 and 92 to move up and down is determined by theresistors 101, 100, 94 and capacitor 99. At some point in time,capacitor 99 will be charged to a voltage sufficient to prevent theactivation of coil 90. At this point, a majority of the DC voltage willbe across capacitor 99, relay coil 90 will be deactivated, and thecontact arm 91 and 92 will be in their up position, disconnecting the ACsignal from terminal TA5.

Since the remote condition sensing device is an SCR, SCR 57 will remainconducting once gated until reset. Thus, break-light 53 will be ignitedand the operator will know which remote sites have been changed fromnight today monitoring. When the operator has time, he will move switch40 into its reset position, breaking the series circuit of SCR 57 withthe DC power source 17 and thus deactivate the SCR 57. At the same time,the operator moves switch 77 into position A for night monitoring.

Thus, the circuits as just described automatically transmit a ringbacksignal to the remote site to indicate that the central office has sensedthe change of position of the remote site switch from night to daymonitoring and automatically transmits an AC signal for a given numberof cycles. When the operator has time, he resets the central office andturns the central office from day to night monitoring'of the remotesite. Thus the present invention has provided an automatic ringbacksystem which will allow the client to leave his premises knowing thathis system is in operation without the necessity of manual manipulationby an operator in the central location.

Though the various indicators have been shown as lights, bells orbuzzers, the power sources have been shown as a DC battery and a20-cycle motor generator set, any substitution of equivalent elementscan be made without deviating from the spirit or scope of the invention.The present automatic ringback system has been described in combinationwith a specific alarm system but may be used with any other type ofalarm system. Although the invention has been described and illustratedin detail, it is to be clearly understood that the same is by way ofillustration and example only and is not to be taken by way oflimitation, the spirit and scope of the invention being limited only bythe terms of the appended claims.

What is claimed is:

1. An alarm system with automatic ringback from a central location to aremote site comprising:

a manually operated remote switch at said remote site connected to saidcentral location;

a remote indicator at said remote site connected to said centrallocation;

a switching means at said central location having a first terminalconnected to said remote indicator and a second terminal connected to asignal source;

a sensing means at said central location connected to said remote switchfor sensing the condition of said remote switch; and

a switch control means at said central location connected to saidsensing means for interconnecting said switching means first and secondterminals for a limited time in response to a first sensed condition;

whereby said remote indicator is activated 'by said signal source forsaid limited time.

2. An alarm system as in claim 1 including a first central indicatorconnected to said sensing means and activated in response to said firstsensed condition until manually reset.

3. An alarm systemas in claim 1 wherein said switch first and secondterminals.

5. An alarm system as in claim 4 including a time delay means connectedto said relay means for delaying the activation of said relay means uponopening of said relay switch.

I 6. An alarm system as in claim 3 including a cycle limiting meansconnected to said cycling means for disabling said cycling means at theexpiration of said limited time.

7. An alarm system as in claim 6 wherein said cycle limiting meanscomprises a resistor-capacitor circuit whose rate of change determinessaid limited time. 1

8. An alarm system as in claim 1 wherein said manually operable remoteswitch has a day and night condition and said first sensed conditionbeing said night ing means, and a third terminal connected to saidringback signal source for automatically interconnecting said first andthird terminals for a fixed du ration in response to a sensed nightposition.

10. An alarm system as in claim 9 wherein said switching means includesa relay means connected to said sensing means for interconnecting saidfirst terminal and said second terminal or interconnecting said firstterminal and said third terminal.

11. An alarm system as in claim 10 wherein said sensing means is abistable means'which remains activated upon sensing said night positionuntil manually reset.

12. An alarm system as in claim 11 wherein said relay means includes aswitch connected in series with said relay means, said relay uponactivation simultaneously opening said series switch and interconnectingsaid 7 switch means first and third terminals.

13. An alarm system as in claim 12 including a capacitor in parallelwith said relay to delay deactivation of said relay upon opening of saidseries switch.

14. An alarm system as in claim 12 including an RC circuit in serieswith said relay whose rate of charge determines the fixed duration.

15. An alarm system as in claim 11 including a first indicator connectedto said sensing means; and manual reset means for resetting said sensingmeans, and said first indicator, and for discharging said RC circuit.

16 An alarm system as in claim 15 including a manual switch connectedbetween said ringback signal source and said third terminal.

17. An alarm system as in claim 2 wherein there is a I correspondingplurality of remote switches, remote indicators, switching means,sensing means, switch control means, and first central indicator; asingle signal source connected to said second terminal of each switchingmeans, and a single second central indicator connected to each of saidsensing means.

18. An alarm system as in claim 17 wherein said single signal source isan alternating current and includes a single direct current sourceconnected to each of said

2. An alarm system as in claim 1 including a first central indicatorconnected to said sensing means and activated in response to said firstsensed condition until manually reset.
 3. An alarm system as in claim 1wherein said switch control means includes a cycling means for causingsaid switching means to repeatedly interconnect and disconnect saidswitching means first and second terminals for the duration of saidlimited time.
 4. An alarm system as in claim 3 wherein said cyclingmeans comprises a relay means connected to said sensing means by a relayswitch for simultaneously opening said relay switch and interconnectingsaid switch means first and second terminals.
 5. An alarm system as inclaim 4 including a time delay means connected to said relay means fordelaying the activation of said relay means upon opening of said relayswitch.
 6. An alarm system as in claim 3 including a cycle limitingmeans connected to said cycling means for disabling said cycling meansat the expiration of said limited time.
 7. An alarm system as in claim 6wherein said cycle limiting means comprises a resistor-capacitor circuitwhose rate of change determines said limited time.
 8. An alarm system asin claim 1 wherein said manually operable remote switch has a day andnight condition and said first sensed condition being said nightcondition.
 9. An alarm system with automatic ringback comprising: aremote switch having a day position and a night position; a remoteringback indicator; a sensing means for sensing said night position ofsaid remote switch; a ringback signal source; and a switching meanshaving a first terminal connected to said remote switch and said remoteringback indicator, a second terminal connected to said sensing means,and a third terminal connected to said ringback signal source forautomatically interconnecting said first and third terminals for a fixedduration in response to a sensed night position.
 10. An alarm system asin claim 9 wherein said switching means includes a relay means connectedto said sensing means for interconnecting said first terminal and saidsecond terminal or interconnecting said first terminal and said thirdterminal.
 11. An alarm system as in claim 10 wherein said sensing meansis a bistable means which remains activated upon sensing said nightposition until manually reset.
 12. An alarm system as in claim 11wherein said relay means includes a switch connected in series with saidrelay means, said relay upon activation simultaneously opening saidseries switch and interconnecting said switch means'' first and thirdterminals.
 13. An alarm system as in claim 12 incluDing a capacitor inparallel with said relay to delay deactivation of said relay uponopening of said series switch.
 14. An alarm system as in claim 12including an RC circuit in series with said relay whose rate of chargedetermines the fixed duration.
 15. An alarm system as in claim 11including a first indicator connected to said sensing means; and manualreset means for resetting said sensing means, and said first indicator,and for discharging said RC circuit.
 16. An alarm system as in claim 15including a manual switch connected between said ringback signal sourceand said third terminal.
 17. An alarm system as in claim 2 wherein thereis a corresponding plurality of remote switches, remote indicators,switching means, sensing means, switch control means, and first centralindicator; a single signal source connected to said second terminal ofeach switching means, and a single second central indicator connected toeach of said sensing means.
 18. An alarm system as in claim 17 whereinsaid single signal source is an alternating current and includes asingle direct current source connected to each of said sensing means.